TypeScript Lab: Missing Image Alt

LAB / EXPLORATION

TypeScript Lab: Missing Image Alt

Planned

LAB 073 — Semantic HTML
Add an alt attribute only when an image lacks one.

LAB TypeScript Lab: Missing Image Alt Preview coming soon

LAB 073

TypeScript Lab: Missing Image Alt

Concept

DOM inspection can infer safe missing semantics without replacing author input.

Concept

DOM inspection can infer safe missing semantics without replacing author input.

Objective & Explanation

What the project should make visible and why the concept matters.

Learning Target

Objective

Add an alt attribute only when an image lacks one.

Explanation

DOM inspection can infer safe missing semantics without replacing author input.

Project Plan

Structure, technologies, data boundary, and source connection.

Structure

project/
├── package.json
├── tsconfig.json
├── index.html
├── styles.css
└── src/
    └── app.ts

Technologies

TypeScript
DOM
HTML
CSS

Data Layer

No persistent data layer. Keep all demonstration values inside the standalone project.

Sandbox Source

src/local-editor/client.ts → semanticAssistHtml()

Build Instructions

Build only the focused behavior, then use the visual layer to inspect it.

Setup

Create the standalone project folder and listed files.

Implement

Implement the smallest version that demonstrates the concept.

Run & Inspect

Change one input and observe the visible output change.

Code & Configuration

Starter configuration plus the focused implementation example.

Focused TypeScript

Implement this behavior first, then alter the input.

const image = document.querySelector("img")!;

if (!image.hasAttribute("alt")) {
  const file = image.src.split("/").pop()?.split(".")[0] ?? "";
  image.setAttribute("alt", file.replace(/[-_]+/g, " "));
}

Starter Configuration

Keep the project independently buildable.

package.json

{
  "type": "module",
  "scripts": { "build": "tsc" },
  "devDependencies": { "typescript": "^7.0.2" }
}

tsconfig.json

{
  "compilerOptions": {
    "rootDir": "./src",
    "outDir": "./dist",
    "target": "ES2022",
    "module": "ES2022",
    "lib": ["ES2022", "DOM"],
    "strict": true,
    "sourceMap": true
  },
  "include": ["src/**/*.ts"]
}

Expected Visual Result

The output is the proof that the concept is working.

Visible Proof

The browser should visibly demonstrate: add an alt attribute only when an image lacks one.

Data: None